When a system with a reservoir requires periodic refilling with fluid, the refilling process may be inconvenient and vulnerable to spills, especially if access constraints make it difficult to bring the mouth of a container of fluid close to the reservoir's fill port. The problem may be exacerbated by the presence of equipment on top of the reservoir, which may obstruct access, and which may be at risk of being damaged by any spilled fluid. Moreover, if a cover is installed over the equipment during operation, it may be necessary to remove it to fill the reservoir. A funnel may be used to fill a reservoir in such a situation, but the use of a funnel may be inconvenient. If cleanliness of the fluid is important, for example, it may be necessary to clean the funnel before each use. In some circumstances it may be necessary for a service technician replenishing the reservoir to support the funnel with one hand while pouring the fluid with the other, an operation that may be difficult if the container of fluid is large or heavy, and that may carry a risk of exposing the hand supporting the funnel to spilled fluid. Thus there is a need for a convenient system for filling a reservoir, especially in situations in which the reservoir has top-mounted equipment protected by a cover.